Study on Grouting Technology for Water Gushing in Sandy Dolomite Stratum with High Water Level
Sandy dolomite is characterized by developed joints and fractures.When the groundwater level is above the tunnel crown and the fractures and joints are densely developed,abundant groundwater can change its flow di-rection under the influence of hydraulic head,accumulating towards the tunnel excavation face and causing water gushing.To reduce construction risks and address the issue of unsatisfied grouting reinforcement quality,the study,based on the Central Yunnan Water Diversion Project,employs field analysis,numerical simulation,and engineering practice methods to investigate grouting parameters such as grouting pressure,grout mix ratio,and grouting thick-ness suitable for moderately sandy dolomite,as well as the corresponding construction techniques.The results indi-cate that in sandy dolomite stratum the grouting length should be controlled within 20 m,the reinforcement range outside the excavation profile should be around 4 m,the final grouting pressure should be controlled within 12 MPa,the grout diffusion radius should be within 1.5 m,and the mix ratio of single-component grout and double-compo-nent grout should be 1∶1.As for the grouting process,it should use long and short pipe combined grouting technology to avoid grout backflow,increase grouting pressure,extend the length of grouting sections,accelerate construction progress,and improve grouting reinforcement quality.
Water diversion tunnelSandy dolomiteWater gushingGrouting technology
NETL
NSTL
万方数据
